By all rights, Wendy Chaves' Algebra II class should be a zoo. She's charged with teaching nearly 50 teenagers at a time at the Alliance Tennenbaum Family Technology High School in Los Angeles. Yet Chaves has never felt more effective. "I don't have to worry about classroom management," she reports. "The kids are engaged."

Why? Her 48 students are all on laptops, working through lessons in Compass Learning,Virtual Nerd and Revolution Prep that Chaves has assigned. Their lessons differ based on what each child has mastered, and the programs spit out data that the fifth-year teacher analyzes so that she knows — long before tests would tell her — when to swoop in and help.

Teaching remains a rewarding career, but there are challenges. More than half of teachers told MetLife they felt stressed several days per week vs. 36% in 1985. One problem? In 2008, 43% of teachers said their classes had such mixed abilities that they couldn't teach effectively. Though some schools sort students (into AP classes, for example), even an "advanced" or "remedial" class can mask diverse abilities.

In an era when technology personalizes everything, it's strange that public education still operates on the assembly line model.

"I would love to be a personal tutor to every one of my students," says Jesse Roe, a math teacher at the Summit San Jose schools in California. "Any time I get closer to that one-on-one experience, I'm more satisfied as a teacher."

Shrinking class sizes is one path to this ideal, but it's not the only way.

At Roe's school, students spend half their math time in small, teacher-led classes and half their time practicing math skills with 100 students working through online lessons, mostly from Khan Academy (a free library of educational videos and problem sets), under the supervision of one teacher and two coaches.

System to keep pace

The Khan programs feed data on performance to these educators, who make sure students don't fall behind. "Being in a blended classroom helps capture their needs in a more systematic way than I could as a single teacher," Roe says.

The results show.

On the nationally benchmarked Northwest Evaluation Association's Measure of Academic Progress test, Summit's 10th-graders achieved greater growth than their peers nationally, with disadvantaged students achieving some of the largest gains.

And that's without holding anyone back. Some of Roe's students mastered Algebra II in one semester and moved on to pre-calculus.

To be sure, technology works best in subjects where there are indisputable right answers, such as math, but the range of adaptive software products is expanding. Start-up costs in a blended school can be high. Though as tablets and personal computers become cheaper, these costs are falling.

If you can put 48 kids in a class — and still have it be "a beautiful thing," as Chaves reports — then technology can help schools capture the productivity gains that it has introduced in most other fields.

Today's cellphones are better and cheaper than in 1992. Why can't our schools be better and cheaper, too?

The "better" part is what ultimately makes educators happier. At KIPP Empower Academy, an elementary school in Los Angeles that employs blended learning, there has been 100% teacher retention for the past three years.

"I always say that when I was teaching in a traditional model, I thought I was a good teacher," Chaves says. Then she saw the data and realized how many students were confused or bored. Reaching all of them is more work, Chaves says, but knowing she's reaching them results in "a much more satisfying experience as a teacher."

Laura Vanderkam, author of What the Most Successful People Do at Work, is a member of USA TODAY's Board of Contributors.

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